H3C Technologies H3C MSR 50 - Manual (Page 134)

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Table 60 Configuration items
Item Description
Preamble
Preamble is a pattern of bits at the beginning of a frame so that the receiver
can sync up and be ready for the real data. There are two different kinds of
preambles:
• Short preamble. A short preamble improves network performance.
Therefore, this option is always selected.
• Long preamble. A long preamble ensures compatibility between access
point and some legacy client devices. Therefore, you can select this option
to make legacy client devices support short preamble.
802.11a/802.11n (5 GHz) do not support this configuration.
Transmit Distance Maximum coverage of a radio.
ANI
Adaptive Noise Immunity (ANI). After the ANI function is enabled, the device
automatically adjusts the noise immunity level according to the surrounding
signal environment to eliminate RF interference.
• Enable—Enables ANI.
• Disable—Disables ANI.
Client Max Count Maximum number of clients that can be associated with one radio.
Fragment Threshold
Maximum length of frames that can be transmitted without fragmentation.
When the length of a frame exceeds the specified fragment threshold value, it
is fragmented.
• In a wireless network where error rate is high, you can decrease the
fragment threshold by a rational value. In this way, when a fragment of a
frame is not received, only this fragment rather than the whole frame needs
to be retransmitted, and thus the throughput of the wireless network is
improved.
• In a wireless network where no collision occurs, you can increase the
fragment threshold by a rational value to decrease acknowledgement
packets and thus increase network throughput.
Beacon Interval
Interval for sending beacon frames. Beacon frames are transmitted at a regular
interval to allow mobile clients to join the network. Beacon frames are used for
a client to identify nearby APs or network control devices.
RTS Threshold
Request to send (RTS) threshold length. If a frame is larger than this value, the
RTS mechanism will be used.
RTS is used to avoid data collisions in a WLAN.
A smaller RTS threshold causes RTS packets to be sent more often, thus
consuming more available bandwidth. However, the more often RTS packets
are sent, the quicker the system can recover from interference or collisions.
In a high-density WLAN, you can decrease the RTS threshold by a rational
value to reduce collisions in the network.
IMPORTANT:
The RTS mechanism occupies bandwidth. Therefore, this mechanism applies only
to data frames larger than the RTS threshold.
DTIM Period
Number of beacon intervals between delivery traffic indication message
(DTIM) transmissions. The device sends buffered broadcast/multicast frames
when the DTIM counter reaches 0.